During an RF procedure, a probe is placed into a target tissue for treating malignant and nonmalignant conditions. The probe is typically provided with an array of electrodes so that RF energy can be supplied to the target tissue.
Various RF devices have been employed to treat a large volume of tissue with a single applicator in a single procedure. One such device employs an array of wire electrodes that deploys and assumes an inverted umbrella shape after reaching the target tissue. When deployed, the inverted umbrella shape of the electrode array may be altered by tissue mechanical resistance or calcifications such that the electrode array exhibits a non-uniform pattern of thermal treatment. Such a non-uniform pattern is undesirable because tissue effects will be affected by the changing distance between adjacent electrodes that diverge or converge.
An alternative approach involves the use of an array of electrodes that have a large diameter. Such an approach is also undesirable because the large electrode array cannot be inserted through the body unless an open surgery is performed. Further, the large electrode array cannot be accommodated through a laparoscopic trocar that has a small diameter of 5 to 10 mm.
Accordingly, there is a need for an improved RF device having electrodes that deploy in a uniform and parallel manner along the length of the electrodes and that can be accommodated in a laparoscopic trocar having a small diameter.